A method for preparing mesoporous silica using gasification slag

Abstract

The present invention discloses a method for preparing mesoporous silica using gasification slag, comprising the following steps: using a ball mill to ball mill dried gasification slag; mixing the gasification slag and acid, stirring and leaching, and then filtering, washing and drying the leachate; adding calcium carbonate to anhydrous ethanol, slowly adding a CTAB solution to the calcium carbonate suspension and stirring; adding ammonia water to the mixture of CTAB and calcium carbonate to adjust the pH, then adding the treated gasification slag and stirring, aging at room temperature, filtering, washing and drying to obtain a filter residue; placing the obtained filter residue in a muffle furnace and calcining it at 500-650°C for 5-8 hours to remove the template; and immersing the calcined product in dilute hydrochloric acid, filtering and drying to obtain mesoporous silica microspheres. The method for preparing mesoporous silica provided by the present invention uses waste gasification slag as raw material, has low preparation cost, and the prepared mesoporous silica has a large specific surface area and good adsorption effect on heavy metal chromium.

Description

Technical Field

[0001] The present invention relates to the technical field of mesoporous silica preparation, and in particular to a method for preparing mesoporous silica by utilizing gasification furnace slag. Background Art

[0002] Silicon dioxide, also known as quartz, crystal, and quartz sand. Due to its excellent physical and chemical properties, silicon dioxide is widely used in many fields, such as glass products, cosmetics, ceramics, coatings, rubber, antibacterial materials, refractory materials, drug carriers, etc. The main preparation methods of silicon dioxide include vapor deposition, Method, chemical precipitation method, microemulsion method, sol-gel method, silicate mineral decomposition method. Among them, the sol-gel method is the most commonly used method for the preparation of silica. Its basic process is that metal alcohol salts undergo hydrolysis and condensation reactions in an acid or alkali alcohol solution to form an oxide sol, which is then aged to form a gel, and finally dried and sintered to obtain product particles. However, the sol-gel method has expensive raw materials and a long preparation time; the chemical precipitation method, also known as the sodium silicate acidification method, mainly uses sodium silicate and inorganic acid as raw materials, and obtains silica particles through precipitation, filtration, washing and drying. Although this method uses low-cost raw materials, the particle size distribution of the prepared silica microspheres is relatively wide, and it is difficult to obtain monodispersed silica microspheres; the vapor deposition method, also known as the dry method, combustion method, or thermal decomposition method, has a basic process of Silane halide reacts with hydrogen and oxygen mixture at high temperature to generate gas-phase silica particles, which are then subjected to a series of subsequent treatments such as cooling, aggregation, separation, and deacidification to obtain nano-silica products. The silica prepared by the gas phase method has good crystal structure, high purity, uniform particle size distribution, and good repeatability. However, this method has high reaction temperature, high requirements on equipment, large investment, and harsh operating conditions; the silicate mineral decomposition method mainly uses non-metallic minerals and their extensions as silicon sources, and adopts precipitation method to prepare white carbon black. This method has a relatively simple manufacturing process and low production cost, and the mesoporous silica material prepared by this method is not much different from other mesoporous silica materials prepared by using expensive silica silicon sources.

[0003] Industrial production in my country generates a large amount of solid waste annually. If not properly handled, this waste is not only a waste of resources but also seriously impacts the ecological environment. Gasification slag is a solid residue left after coal is gasified and burned in a gasifier. Its physical composition is directly influenced by factors such as the structure of the original coal, ash and sulfur content, and the gasification and calcination process. It primarily consists of fumed silica, alumina, calcium oxide, and fumed carbon, making it a common solid waste. The current main treatment method is to stockpile this slag for centralized processing and reuse, which not only occupies a large amount of farmland but also seriously pollutes the environment. For a long time, slag has been used as a building material, such as for paving roads, bridges, and building construction, but its added value is relatively low. Therefore, we propose to utilize the silicon in gasification slag to prepare mesoporous silica materials. This material can be widely used in adsorption, catalyst supports, medicine, and new energy fields. This effectively solves the problem of harmless disposal and high-value-added utilization of this waste, with excellent economic and environmental benefits. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing mesoporous silica using gasification furnace slag. By using waste gasification furnace slag as raw material, the preparation cost of mesoporous silica is greatly reduced, and the difficult problems of harmless disposal and high value-added utilization of such waste are effectively solved. It has good economic and environmental benefits. In addition, the mesoporous silica prepared by the present invention has the characteristics of large specific surface area and good adsorption effect on heavy metals such as chromium, and has good prospects for industrial application.

[0005] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions:

[0006] A method for preparing mesoporous silica using gasification slag comprises the following steps:

[0007] (1) Drying the gasification slag at 100-120° C. for 2-5 hours;

[0008] (2) ball milling the dried gasification slag to 200-500 mesh;

[0009] (3) adding the ball-milled gasification slag and the acid solution into a stirrer, stirring and leaching, and then filtering, washing, and drying the leachate;

[0010] (4) adding calcium carbonate powder to anhydrous ethanol, ultrasonically dispersing and filtering, then slowly adding cetyltrimethylammonium bromide solution to the filtered calcium carbonate suspension and stirring thoroughly;

[0011] (5) adding ammonia water to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 9-11, then adding the gasification slag dried in step (3), stirring thoroughly, and then standing and aging at room temperature to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0012] (6) placing the filter residue obtained in step (5) in a muffle furnace and calcining at 500-650° C. for 5-8 hours to remove the template;

[0013] (7) The calcined product is immersed in dilute hydrochloric acid for 10 to 20 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0014] In the above technical solution, step (2) uses a ball mill to ball mill the gasification slag, which not only crushes the gasification slag to obtain a powder with a smaller particle size, but more importantly, mechanically activates the gasification slag through ball milling to destroy the inert surface of the gasification slag;

[0015] In step (3), adding an acid solution to the gasification slag can dissolve the metal oxides in the slag;

[0016] Adding calcium carbonate in step (4) can provide a carrier for preparing silica microspheres;

[0017] In step (4), adding anhydrous ethanol to calcium carbonate can better disperse the calcium carbonate to form mesoporous silica microspheres of uniform size;

[0018] After calcination in step (7), CaCO3 can be removed by soaking in dilute hydrochloric acid.

[0019] Furthermore, the acid solution in step (3) is hydrochloric acid, the concentration of hydrochloric acid is 1 to 6 mol / L, and the leaching time is 0.5 to 3 hours.

[0020] Furthermore, in step (3), the concentration of hydrochloric acid is 3 mol / L, and the leaching time is 2 hours.

[0021] Furthermore, in step (3), the solid-liquid ratio of silicon dioxide to acid solution is 1:2-5.

[0022] Furthermore, in step (4), the molar ratio of hexadecyltrimethylammonium bromide to calcium carbonate is 1:5-10.

[0023] Furthermore, in step (4), the molar ratio of hexadecyltrimethylammonium bromide to calcium carbonate is 1:8.

[0024] Furthermore, in step (4), the ultrasonic dispersion time is 20 to 60 minutes, and the stirring time is 0.5 to 1.5 hours.

[0025] Furthermore, in step (5), the molar ratio of the gasification slag to hexadecyltrimethylammonium bromide is 1:0.1 to 0.6.

[0026] Furthermore, in step (5), the molar ratio of gasification slag to hexadecyltrimethylammonium bromide is 1:0.3.

[0027] Furthermore, in step (6), the calcination temperature is 550° C. and the calcination time is 6 hours.

[0028] Furthermore, the concentration of the dilute hydrochloric acid in step (7) is 0.1 to 1 mol / L.

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention provides a method for preparing mesoporous silica using gasification slag, which uses waste gasification slag as raw material, greatly reduces the preparation cost of mesoporous silica, effectively solves the problem of harmless treatment and high value-added utilization of such waste, and has good economic and environmental benefits;

[0031] (2) The mesoporous silica prepared by the mesoporous silica preparation method of the present invention has the characteristics of large specific surface area and good adsorption effect on heavy metals such as chromium, and has good industrial application prospects. DETAILED DESCRIPTION

[0032] The present invention provides a method for preparing mesoporous silica using gasification furnace slag. To make the objectives, technical solutions, and effects of the present invention more clear and explicit, the present invention is further described below in detail. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0033] Example 1

[0034] This embodiment 1 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0035] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0036] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 350 mesh;

[0037] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0038] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0039] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0040] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0041] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0042] The mesoporous silica microspheres prepared in Example 1 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 79.6%.

[0043] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 1 was tested and found to be 856 m 2 / g; XRD detection was performed on the mesoporous silica microspheres prepared in Example 1, which showed an ordered mesoporous structure.

[0044] Example 2

[0045] This embodiment 2 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0046] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0047] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 350 mesh;

[0048] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0049] (4) 30 g of calcium carbonate powder was added to 172 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0050] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0051] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0052] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0053] The mesoporous silica microspheres prepared in Example 2 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 72.4%.

[0054] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 2 was tested, and the specific surface area was 729 m 2 / g.

[0055] Example 3

[0056] This embodiment 3 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0057] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0058] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 350 mesh;

[0059] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0060] (4) 60 g of calcium carbonate powder was added to 345 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 270 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0061] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0062] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0063] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0064] The mesoporous silica microspheres prepared in Example 3 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 66.2%.

[0065] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 3 was tested and found to be 624 m 2 / g.

[0066] Example 4

[0067] This embodiment 4 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0068] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0069] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 350 mesh;

[0070] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0071] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0072] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 13.8 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0073] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0074] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0075] The mesoporous silica microspheres prepared in Example 4 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 60.7%.

[0076] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 4 was tested and found to be 542 m 2 / g.

[0077] Example 5

[0078] This embodiment 5 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0079] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0080] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 350 mesh;

[0081] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0082] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0083] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 2.3 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0084] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0085] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0086] The mesoporous silica microspheres prepared in Example 5 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 73.1%.

[0087] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 5 was tested, and the specific surface area was 771 m 2 / g.

[0088] Example 6

[0089] This embodiment 6 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0090] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0091] (2) placing the dried gasification slag into a planetary ball mill and ball-milling the dried gasification slag to about 200 mesh;

[0092] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0093] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0094] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0095] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0096] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0097] The mesoporous silica microspheres prepared in Example 1 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 69.7%.

[0098] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 6 was tested and found to be 693 m 2 / g.

[0099] Example 7

[0100] This embodiment 7 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0101] (1) Take the waste gasification slag and dry it at 100°C for 3 hours;

[0102] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 500 mesh;

[0103] (3) adding the ball-milled gasification slag and 3 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0104] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0105] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0106] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0107] (7) The calcined product was immersed in 0.5 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0108] The mesoporous silica microspheres prepared in Example 7 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 76.4%.

[0109] In addition, the specific surface area of ​​the mesoporous silica microspheres prepared in Example 7 was tested and found to be 883 m 2 / g.

[0110] Example 8

[0111] This embodiment 8 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0112] (1) Take the waste gasification slag and dry it at 120°C for 2.5 hours;

[0113] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 500 mesh;

[0114] (3) adding the ball-milled gasification slag and 4 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0115] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0116] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 11, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 24 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0117] (6) calcining the filter residue obtained in step (5) in a muffle furnace at 560° C. for 5 hours to remove the template;

[0118] (7) The calcined product was immersed in 0.6 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0119] The mesoporous silica microspheres prepared in Example 8 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 75.9%.

[0120] Example 9

[0121] This embodiment 9 provides a method for preparing mesoporous silica using gasification slag, comprising the following steps:

[0122] (1) Take the waste gasification slag and dry it at 130°C for 3 hours;

[0123] (2) placing the dried gasification slag into a planetary ball mill and milling the dried gasification slag to about 500 mesh;

[0124] (3) adding the ball-milled gasification slag and 4 mol / L hydrochloric acid solution into a stirrer and stirring and leaching for 2 hours, then filtering, washing, and drying the leachate to obtain dry slag powder;

[0125] (4) 48 g of calcium carbonate powder was added to 276 mL of anhydrous ethanol, ultrasonically dispersed for 30 min, and then filtered; 21.86 g of hexadecyltrimethylammonium bromide was added to 216 mL of deionized water to prepare a solution, and the hexadecyltrimethylammonium bromide solution was slowly added to the filtered calcium carbonate suspension and stirred thoroughly for 1 hour;

[0126] (5) adding aqueous ammonia to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 10, then adding 4.6 g of the dried slag powder obtained in step (3), stirring thoroughly for 30 min, and then standing and aging at room temperature for 20 hours to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue;

[0127] (6) placing the filter residue obtained in step (5) in a muffle furnace at 550° C. and calcining for 6 hours to remove the template;

[0128] (7) The calcined product was immersed in 0.7 mol / L dilute hydrochloric acid for 12 hours, and then filtered and dried to obtain mesoporous silica microspheres.

[0129] The mesoporous silica microspheres prepared in Example 7 were placed in 30 mL of 100 mg / L Cr 3+ The solution was stirred at 200 rpm for 2 hours at room temperature, and then Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 77.3%.

[0130] Comparative Example 1

[0131] This comparative example 1 provides a method for preparing mesoporous silica, wherein the raw material is sodium carbonate and the preparation method is a hydrothermal method, and the specific steps are as follows:

[0132] 30 g of sodium silicate was dissolved in 500 mL of deionized water, and 12 g of CTAB was dissolved in 68 mL of deionized water. The CTAB solution was then slowly added to the sodium silicate solution, and the pH was adjusted to 9 with sulfuric acid. The mixed solution was then magnetically stirred for 3 hours. The obtained solution was placed in a reactor lined with polytetrafluoroethylene and subjected to a hydrothermal reaction at 110° C. for 18 hours. After the reaction was completed, it was aged at low temperature for 48 hours and then filtered. The filtered residue was dried and calcined in a muffle furnace at 550° C. for 6 hours to remove the template. Finally, the calcined product was ground to obtain mesoporous silica.

[0133] Take the above mesoporous silica and place it in 30mL of 100mg / L Cr 3+The solution was stirred at 200 rpm for 2 h at room temperature and Cr was determined by ICP-OES. 3+ The concentration of Cr 3+ The removal rate is 53.8%, and its specific surface area is 488m 2 / g.

[0134] Compared with the mesoporous silica microspheres prepared by the hydrothermal method, the mesoporous silica microspheres prepared by the preparation method of the present invention have better adsorption effect on heavy metal chromium.

[0135] It should be noted that the parts not described in the present invention can be implemented by adopting or drawing on existing technologies.

[0136] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A method for preparing mesoporous silica using gasification slag, characterized in that: The steps include: (1) Drying the gasification slag at 100-120° C. for 2-5 hours; (2) ball milling the dried gasification slag to 200-500 mesh; (3) adding the ball-milled gasification slag and the acid solution into a stirrer, stirring and leaching, and then filtering, washing, and drying the leachate; (4) adding calcium carbonate powder to anhydrous ethanol, ultrasonically dispersing and filtering, then slowly adding cetyltrimethylammonium bromide solution to the filtered calcium carbonate suspension and stirring thoroughly; (5) adding ammonia water to a mixture of hexadecyltrimethylammonium bromide and calcium carbonate, adjusting the pH of the mixture to 9-11, then adding the gasification slag dried in step (3), stirring thoroughly, and then standing and aging at room temperature to obtain a white solid, and then filtering, washing, and drying the aged mixture containing the white solid to obtain a filter residue; (6) placing the filter residue obtained in step (5) in a muffle furnace and calcining at 500-650° C. for 5-8 hours to remove the template; (7) The calcined product is immersed in dilute hydrochloric acid for 10 to 20 hours, and then filtered and dried to obtain mesoporous silica microspheres.

2. The method for preparing mesoporous silica using gasification slag according to claim 1, wherein: The acid solution in step (3) is hydrochloric acid, the concentration of hydrochloric acid is 1 to 6 mol / L, and the leaching time is 0.5 to 3 hours.

3. The method for preparing mesoporous silica using gasification slag according to claim 2, wherein: In step (3), the concentration of hydrochloric acid is 3 mol / L, and the leaching time is 2 hours.

4. The method for preparing mesoporous silica using gasification slag according to claim 1, wherein: In the step (3), the solid-to-liquid ratio of silicon dioxide to the acid solution is 1:2-5.

5. The method for preparing mesoporous silica using gasification slag according to claim 1, wherein: In the step (4), the molar ratio of hexadecyltrimethylammonium bromide to calcium carbonate is 1:5-10.

6. The method for preparing mesoporous silica using gasification slag according to claim 5, characterized in that: The molar ratio of hexadecyltrimethylammonium bromide to calcium carbonate in step (4) is 1:

8.

7. The method for preparing mesoporous silica using gasification slag according to claim 1, characterized in that: In the step (4), the ultrasonic dispersion time is 20 to 60 minutes, and the stirring time is 0.5 to 1.5 hours.

8. The method for preparing mesoporous silica using gasification slag according to claim 1, characterized in that: In the step (5), the molar ratio of the gasification slag to the hexadecyltrimethylammonium bromide is 1:0.1 to 0.

6.

9. The method for preparing mesoporous silica using gasification slag according to claim 8, characterized in that: In the step (5), the molar ratio of the gasification slag to the hexadecyltrimethylammonium bromide is 1:0.

3.

10. The method for preparing mesoporous silica using gasification slag according to claim 1, characterized in that: In the step (6), the calcination temperature is 550° C. and the calcination time is 6 hours.

11. The method for preparing mesoporous silica using gasification slag according to claim 1, characterized in that: The concentration of the dilute hydrochloric acid in step (7) is 0.1 to 1 mol / L.